Hermit crabs from Brazil: Family Diogenidae (Crustacea: Decapoda: Paguroidea), except Paguristes
Author
Nucci, Paulo Ricardo
Author
Melo, Gustavo Augusto Schmidt De
text
Zootaxa
2015
3947
3
327
346
journal article
10.11646/zootaxa.3947.3.2
6173bd73-5471-4c1e-a758-5481ffbd97b5
1175-5326
240452
4BEA9B2D-E883-43B5-AE74-1EBBD0D4D684
Loxopagurus loxochelis
(
Moreira, 1901
)
(
Figs 4
A, 7A)
Pagurus loxochelis
Moreira, 1901
: 24
, pl.2, fig. 1a–f.
Loxopagurus loxochelis
.—
Forest, 1964
: 281
, figs 1–10.—
Forest & Saint Laurent, 1968
: 112
, figs 66, 67.—
Coelho & Ramos, 1972
: 170
.—Scelzo, 1973: 169; 1976: 44.—
Scelzo & Boschi, 1973
: 208
.—
Boschi, 1979
: 138
.—
Coelho & Ramos-Porto, 1986
: 52
.—
Hebling & Rieger, 1986
: 72
, fig. 6.—
Rieger, 1998
: 423
.—McLaughlin
et al.
, 2010: 22.
Loxopagurus loxocheles
.—[
sic
]
Melo, 1999
: 68
, fig. 24 [
error
].
Material examined
.
Brazil
: Rio de Janeiro—Proj.
Ilha
Grande, st. 258, 1 spec. (MZUSP-4658); st. 170, 1 spec. (MZUSP-4648); st. 273, 1 spec. (MZUSP-4660); st. 207, 1 spec. (MZUSP-4661); st. 210, 1 spec. (MZUSP- 4650); st. “J”, 16 spec. (MZUSP-4645); st. 99, 1 spec. (MZUSP-4651); st. 101, 3 spec. (MZUSP-4666); st. 12, 3 spec. (MZUSP-4652); st. 58, 1 spec. (MZUSP-4657); st. 236, 3 spec. (MZUSP-4646); st. 304, 1 spec. (MZUSP- 9456); Cabo de
São Tomé
, 1 spec. (MZUSP-4659); São Paulo—Proj. Monitoramento, 3 spec. (MZUSP-13349); Proj. Integrado, st. 21, 12 spec. (MZUSP-8732); 1 spec. (MZUSP-8760); st. 12, 2 spec. (MZUSP-8761); st. 36, 1 spec. (MZUSP-8764); 1 spec. (MZUSP-8765); st. fixa 2, 1 spec. (MZUSP-8758); st. 48, 1 spec. (MZUSP-8767); st. 6, 4 spec. (MZUSP-8759); st. 22, 1 spec. (MZUSP-8762); st. 42, 2 spec. (MZUSP-8766); st. 24, 1 spec. (MZUSP-8763); Santos, 2 spec. (MZUSP-13141); 1 spec. (MZUSP-4647); Praia Grande, 7 spec. (MZUSP- 13319); 4 spec. (MZUSP-13312); Cananéia, 4 spec. (MZUSP-4669); 1 spec. (MZUSP-6217); Santa Catarina— Imbituba, 3 spec. (MZUSP-9397); st. 14, 6 spec. (MZUSP-8645); st. 1, 4 spec. (MZUSP-8644); 3 spec. (MZUSP-8643); 2 spec. (MZUSP-9392); Itapocoróia, 11 spec. (MZUSP-4663); Rio Grande do Sul—5 spec. (MZUSP-13722); Proj.
GEDIP
, st. 558, 1 spec. (MZUSP-4681); st. 415, 6 spec. (MZUSP-4677); 1 spec. (MZUSP-4653); 2 spec. (MZUSP-4655); 15 spec. (MZUSP-4676); 1 spec. (MZUSP-4683); 40 spec. (MZUSP- 4688); 2 spec. (MZUSP-4670); 2 spec. (MZUSP-4672); 10 spec. (MZUSP-4682); 20 spec. (MZUSP-4675); 1 spec. (MZUSP-4654); 1 spec. (MZUSP-4684); st. 407, 2 spec. (MZUSP-4674); st. 577, 1 spec. (MZUSP-4673); st. 283, 5 spec. (MZUSP-4687); st. 1643, 6 spec. (MZUSP-4668); 3 spec. (MZUSP-4680); st. 572, 11 spec. (MZUSP-4678); 1 spec. (MZUSP-4649); st. 417, 2 spec. (MZUSP-4667); st. 1645, 1 spec. (MZUSP-4665); st. 557, 1 spec. (MZUSP-4656); st. 1700, 1 spec. (MZUSP-4664); st. 1699, 1 spec. (MZUSP-4671); 3 spec. (MZUSP-4685); st. 397, 1 spec. (MZUSP-4643); st. 1660, 2 spec. (MZUSP-4679); st. 430, 1 spec. (MZUSP- 4662); st. 1687, 2 spec. (MZUSP-4686).
Diagnosis
. Shield as long as broad. Antennular peduncle overreaching cornea by half length of last segment. Left cheliped much stronger than right. Dactyls slightly curved. Width of propodus in the median region half length of ventral margin. Dorsolateral and mesial faces of carpus covered by corneous tubercles and separated by row of tooth shaped tubercles. Merus with mesial and lateral faces separated at proximal third by salient ridge armed with corneous spinules. First ambulatory legs reaching end of left cheliped, with strong mesial inwards. Dactyl with row of corneous tubercles on dorsal face; in the lateral and mesial faces, 3 longitudinal striae separated by rows of corneous granules.
Distribution
. Western Atlantic—Brazil (from Bahia to Rio Grande do Sul),
Uruguay
and
Argentina
.
Remarks
.
Forest (1964)
described the genus
Loxopagurus
based on
Pagurus loxochelis
(
Moreira, 1901
)
, highlighting the many similarities between his new genus and
Isocheles
, mainly in relation to the aspect of the anterior region of the body, especially the forms of the shield, antennal peduncles and scales, some mouth parts, etc.
Forest & Saint Laurent (1968)
mention again the strong resemblance between
Isocheles
and
Loxopagurus
, except for the remarkable heterochely presented by
Loxopagurus
. However, in this same work, the authors mention that a species of
Isocheles
from
Guatemala
(not described) also features pronounced heterochely, weakening this character as the principal in separating the two genera. In addition, studies on the post embryonic development from both species showed extreme similarity between the larval stages, as it had already been mentioned by
Hebling (1978)
. In his unpublished doctoral thesis,
Nucci (2002)
suggested that due to these important similarities, the two genera may be synonymous. Unfortunately,
Mantelatto
et al
. (2006)
misunderstood what was suggested by
Nucci (2002)
and published the article cited above with mistaken information based on unpublished data. In this article the authors mention that
Nucci (2002)
proposed to synonymize
Isocheles sawayai
and
Loxopagurus loxochelis
.
What was suggested by
Nucci (2002)
, however, was that the two genera could be synonymous, but not the species. Therefore, a more comprehensive study of the two genera is still necessary, which involves the description of all the species not yet described of the genus
Isocheles
and the use of two or more molecular markers, in order to obtain the best phylogenetic estimate of
Loxopagurus
in relation to
Isocheles
. Probably, this is the only way we will be able to confirm or refute the hypothesis of synonymy of the two genera.